Friday, April 9, 2010

Soil Nutrition

We're on the cusp of 5 weeks before the last frost here in the Hudson Valley! Have you planted all that stuff you said you'd plant indoors (!)? Are your peas in the ground (yes!)? Garlic come up (yes!)? are you preparing your beds, repairing fencing (and garden tools and hats and hoses), adding nutrients, and finalizing plans (err...mostly)?

Preparing rich beds for Spring - soil nutrition and amendments
It's easy to see the larger picture when you look at your garden soil. Rich, black soil with lots of worms, easy-to-work texture, lots of air, and a soft, sweet, earthy smell are the obvious markers of good soil. What's hard to see is the details - who know how much Nitrogen or Potassium you have in there? Or what the pH is?

You want to make sure your plants are healthy and well fed this summer. If you haven't tested your soil for pH and basic nutrient levels, I would go ahead and send in a sample to Cornell co-operative extension (if you're in New York. In Jersey it's Rutgers, in Massachusetts it's UMass). You can also find diy soil pH tests at most nurseries, though I suggest building a relationship with your extension office - they're a huge help and a wonderful resource. To get a sample, dig up a good 6-inch deep cross-section of soil from your garden, put it in a mason jar or a plastic bag, and drop it off or mail it too the nearest extension office, asking for a basic soil test (they probably have a form on their website to fill out). It'll take 2-6 weeks to get the results back, during which time you can ask any gardening/farming neighbor what they add to their soil. Asking neighbors is a great way to find out what your soil will need, and just about everything else about gardening in your area.

The most common soil nutrient folks add to their soil here is lime to neutralize acidic soil. It's important to have a balanced soil pH because many dangerous soil chemicals dissolve in solution at an excessively low or high pH causing the plant to uptake them more easily, while good chemicals and elements, which a plant needs to survive, cannot be taken up by the plants in extremes of pH. pH stands for "parts Hydrogen," low pH is acidic while high pH values are alkaline or basic, a pH of 7 is neutral. Ideal soil pH is between 6.3-6.8. If you find that your soil is acidic (a pH lower than 6), add lime (follow instructions on the bag) or wood ash (I would just spread it liberally on the beds, which is what we do in my landlord's garden all winter). Since soil acidity is determined by the bedrock in your area, it will be a pervasive and consistent feature of your garden, and adding lime will be an annual endeavor (unless you build really effective raised beds).

After incorporating lime, you want to make sure that your plants have the nutrients they need for the coming year. The best soil amendment is finished compost (or fully composted manure). Not only does it add organic material and living nutrients, it also improves soil texture, pH, color (and therefore heat retention), beneficial bacteria, and is an all-around wonder drug for your garden soil. do NOT add raw compost or manure to spring garden beds (the one exception to this rule is rabbit manure, and if you have access to that, you've struck gold). Raw manure will burn delicate plant roots while raw compost will take hold up nutrients in its decomposition that you want to go to the plants. (In the fall, the rules are different, but we're not in the fall, are we?). If you don't have finished compost, go get yourself a bunch of manure, straw/mulch hay/leaves, and raw food scraps and promise yourself that next year at this time you will have at least some finished compost. In the mean time, if your soil is depleted (simple test - have you grown a heavy-feeder vegetable crop there last year? If so, your soil is depleted), you can use blood meal, bone meal, soy meal, etc etc etc to increase nutrient levels in the soil. Go to the nursery and get a well-balanced, organic soil additive and spread as per directions. Note that peas and beans are, in their own right, soil nutrients, and beds that will be planted with peas or beans can go without a heavy dose of additional nutrients, though I would add a little bit if you think your soil is very depleted (a 3-year rotation with beans is a classic rotation for soil nutrition).

phew! Got all that? Now that you know what spring is like, there's a lot of good reasons to put your garden to rest properly in the fall (namely that it saves you a lot of trouble come spring). Start asking around at local farms now to see if you can take one or a few pick-up truck loads of manure (1 pick-up load per 1-2 people being fed out of the garden is an easy estimate) so that you have it on hand when you put your beds to rest this fall. The longer it sits composting, the better.

As a side-note: P-K-N ratios seen on fertilizers, often just listed as 20-10-20 or something like that, stands for the amount of Potassium-Phosphorous (usually in the form of Potash)-Nitrogen in a fertilizer.

Also, I'll get around to kombucha one of these days, I promise.

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